GaN has been expected as a material of power device for the next generation with high breakdown voltage and low on-resistance. This is because GaN has characteristics such that a band gap is wide and a dielectric breakdown voltage is high.
As an example of power device using GaN, there is a vertical MOS (metal-oxide-semiconductor) FET (field effect transistor).
However, in a conventional vertical MOSFET, there is a problem that a threading dislocation exists in crystal of GaN between a source and a drain, and a leak current flows by taking the dislocation as a leak path.
Patent Literature 1: Japanese Laid-open Patent Publication No. 2006-313859